G'day Duncan.
I am a new beginner as well and will be in Sydney for the next week before moving back to Darwin. I am also looking for a good place to fly. I am staying in the sutherland area and have got most days free as I am on holidays! The places I have flown at so far are at Rooty Hill, Pioneer Park in Maroubra and Wanda park at Cronulla. The best so far was Wanda due to the excellent wind but there is not too much room to move and there are a few people there. Pioneer park had the most room but the day I went there the wind was average and its a long way to travel! Hope that helps a little bit.